In this poster, we describe the major design features of the
James Webb Space Telescope (JWST) Integrated Science
Instrument Module (ISIM).

The JWST mission is under development by NASA in partnership
with the European and Canadian Space Agencies for launch
during 2013. The JWST is designed to enable a five year
science mission that is focused on four themes: [1]
observation of the first luminous objects after the Big
Bang, [2] the assembly of these objects into galaxies, [3]
the birth of stars and planetary systems, and [4] the
formation of planets and the origins of life.

The above science themes require high sensitivity and
HST-like angular resolution over the near- to mid-infrared
spectrum. A ~40 K cryogenic radiatively cooled telescope
with a 25 m2 collecting area was selected to meet these
requirments. A mission architecture involving a Lissajous
orbit about the Earth-Sun L2 point was chosen to meet
optical stability and data downlink requirments. A modular
flight segment architecture was selected to enable
incremental integration and test of the cryogenic payload.
The ISIM is one key feature of this modular architecture
that enables a feasible cryogenic test program.

The ISIM element is the science instrument payload of the
observatory. It contains ~70 million infrared detector
pixels allocated among four science instrument systems and a
fine guidance sensor system. Brief instrument descriptions
are available at: www.stsci.edu/jwst/docs/flyers. The ISIM
also contains a passive ~40 K thermal control system, a ~6 K
cryo-cooler system, a command and data handling system, a
flight software system, and an optical metering structure
system. The ISIM element is responsible for acquisition of
the JWST science data, fine guidance data for telescope
pointing control, and wavefront sensing data for in-flight
adjustment of the telescope optics. Further information
about the JWST mission is available at: www.jwst.nasa.gov.